Why nuclear fusion is not used to generate electricity?

Normally we use nuclear fission process to generate electricity in the nuclear power plant by using nuclear power reactors. The process of breaking of a nucleus into several neutrons which releases large amount of energy is called nuclear fission. The neutrons released again and hit another nucleus and in turn several neutrons and energy are prduced. Thus, the chain reaction takes place in the nuclear power plants. This reaction is effected in a very controlled manner in the nuclear reactors. The control rods are placed in the reactors to cool the nuclear reactor frequently. The energy released in the water converts the water into steam and this steam runs the turbines and in turn electricity is generated by using nuclear fission. This energy is called nuclear energy.
                                               Till now, we generate electricity by using nuclear fission process but not using fusion process. When the two lighter nuclei combines to form a heavier nuclei which releases a large amount of energy is called nuclear fusion. This nuclear fusion process takes place in sun. In sun, two hydrogen combine to form a helium nuclei. To create a nuclear fusion process in the earth, it needs a large amount of temperature as well as pressure. Hence, it is impossible to generate such high pressure and temperature. Even if we carried out the process by generating high pressure and temperature, we don't know how the effect will be and what will be the result. The question remains unanswered.